Abstract
In this work we have performed total-energy calculations of the chemisorption properties and STM images of Pt (111) ( × )R30°/CO Surface; STM Image; ChemisorptionR30°/CO surface by using the density functional theory (DFT) and the projector-augmented wave (PAW) method. The calculations show that carbon monoxide molecule (CO) adsorbs on FCC site in the Pt (111) ( × )R30°/ surface is energetically favored by the GGA-PBE XC-functional, this is in agreement with most of the theoretical calculations which is using different XC-functional at the most. However, these results strongly conflicted with the existing experiments. Actually the calculated work function for the FCC adsorption is quite different from the experiments while the atop one is in good agreement with experiments. We speculate that the atop adsorption for (CO is favorable for the adsorption case at the most. Furthermore, we have calculated the scanning tunneling microscopy (STM) images for both adsorption geometries and suggest that there should be existed remarkable differences in the STM images. The present work provides a faithful criterion accounting for the local surface geometry in Pt (111) ( × )R30°/CO surface from surface work functions and STM images instead of totalenergy calculations.
Highlights
CO adsorption is an important mechanistic step in the chemical reaction pathway of many heterogeneous catalytic reactions [1]
The Kohn-Sham equations are solved by applying the Vienna ab-initio Simulation Package (VASP) [17,18], which is a complex package for performing ab-initio quantum-mechanical molecular dynamics (MD) simulations using ultrasoft pseudo-potentials (USPP) [19] or PAW method [14,17] and a plane wave basis set
It is noticed that the density-functional theory (DFT) calculations based on PW91 type general gradient approximation (GGA) [29] yielded a very similar surface relaxation with ours
Summary
CO adsorption is an important mechanistic step in the chemical reaction pathway of many heterogeneous catalytic reactions [1]. In these catalytic reactions, transition metals play a dominate role in considerably enhancing the rate of reaction that involves the adsorption, diffusion and bond dissociation steps of carbon monoxide [2]. One of the important examples is the adsorption of CO on the Pt (111) surface due to the high economic and environmental implications in materials science [3]. For Pt (111) ( 3 × 3 )R30 ̊ attentionem, it has attracted considerable attentions in the past decade.
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